AVForums

Our philosophy in our forums, reviews, podcasts and feature videos is to promote audio and visual excellence by gathering and sharing the best information and resources available.

Help

To begin please visit our help section »

Not a Member Yet?

It only takes a minute to start enjoying the benefits of AVForums membership, and it's free!

Member Log in

placing a dlp projector off centre

Post Reply
Old 29-05-2005, 12:21 PM   #1
Ex Member
 
scouse258's Avatar
Join Date: May 2005
Location: Newcastle
Thanks: Gave 1, Got 5
Posts: 411
Question placing a dlp projector off centre

hello

im currently building a cinema in my loft

i have a hitachi 5200 42" plasma in my living room but thought - hell lets do out the loft.

MY PROBLEM...

the centre pillar keeping up the loft is in the way of projecting an image dead centre and so i was considering placing the projector slightly off straight - just behind and to the right of the column

The projector is a BENQ PE8700 bought from Ebay

It is a wonderful lifelike presentation when viewing without zoom but loses something when you use the zoom, the picture becomes a tad more blurry.

projecting from 3.2m gives me a relitively small image whilst from 3.5 (off centre) it is far more respectible - its amazing how a few more inches can improve your life

So - what i have is digital keystone correction but i am guessing is that i need a projector with lense shift ?

i am keeping the projector so with this in mind - does this mean i am knackered and will simply have to use the lense zoom to fill the screen??

cheers for your time

PS - is the best colour for the walls of the cinema matt black and the carbet a dark colour too?
  Quote
Old 29-05-2005, 12:48 PM   #2
Prominent Member
 
cyberheater's Avatar
Join Date: Apr 2003
Location: Scotland
Experience Points:
17,620, Level: 32
Points: 17,620, Level: 32 Points: 17,620, Level: 32 Points: 17,620, Level: 32
Activity: 0.3%
Activity: 0.3% Activity: 0.3% Activity: 0.3%
Thanks: Gave 41, Got 153
Posts: 3,007
Have you thought about mounting a mirror on the center support.

You could have the projector mounted nearer to the screen but pointing to the support and the mirrow would bounce the light back to the screen so you'd get a full centered screen.

Worth a look.

And in terms of colour. It doesn't have to be black. You could use a dark midnight blue
  Quote
Old 29-05-2005, 4:09 PM   #3
Ex Member
 
scouse258's Avatar
Join Date: May 2005
Location: Newcastle
Thanks: Gave 1, Got 5
Posts: 411
move the screen?

cheers for your thoughts, however, i think the mirror idea is a horrible one

the difference from centre to off centre is about 6 inches so i may simply point it straight and have the screen off centre

any more comments guys?

Chris
  Quote
Old 29-05-2005, 5:07 PM   #4
Conspicuous Member
 
PJTX100's Avatar
Join Date: Dec 2004
Experience Points:
16,232, Level: 30
Points: 16,232, Level: 30 Points: 16,232, Level: 30 Points: 16,232, Level: 30
Activity: 1.1%
Activity: 1.1% Activity: 1.1% Activity: 1.1%
Thanks: Gave 402, Got 566
Posts: 8,102
This is where optical lens shift comes into its own.

If you haven't got that, or horizontal keystone correction (not many PJs do I think) then an offcentre screen seems to be the only solution (other than Cyber's mirror idea, which can work effectively if set up correctly)...PJ
  Quote
Old 30-05-2005, 10:22 AM   #5
Prominent Member
 
cyberheater's Avatar
Join Date: Apr 2003
Location: Scotland
Experience Points:
17,620, Level: 32
Points: 17,620, Level: 32 Points: 17,620, Level: 32 Points: 17,620, Level: 32
Activity: 0.3%
Activity: 0.3% Activity: 0.3% Activity: 0.3%
Thanks: Gave 41, Got 153
Posts: 3,007
Quote:
Originally Posted by scouse258
cheers for your thoughts, however, i think the mirror idea is a horrible one

the difference from centre to off centre is about 6 inches so i may simply point it straight and have the screen off centre

any more comments guys?

Chris
Just out of curiosity. Why is it a horrible idea? Lot's of folks have used the technique to resolve set up issues.
  Quote
Old 30-05-2005, 8:33 PM   #6
Ex Member
 
scouse258's Avatar
Join Date: May 2005
Location: Newcastle
Thanks: Gave 1, Got 5
Posts: 411
simple - ignorance on how to do do it - how big a mirror do you need - etc

i thought a knew a lot then i visited the forum and found out i know bugga all!!!

at least sky are now gonna do HD via component from day1 making my plasma not so outdated after all!!
  Quote
Old 30-05-2005, 8:47 PM   #7
Distinguished Member
 
Gordon @ Convergent AV's Avatar
Join Date: Jul 2000
Location: Living in Surrey, covering UK!
Experience Points:
41,385, Level: 49
Points: 41,385, Level: 49 Points: 41,385, Level: 49 Points: 41,385, Level: 49
Activity: 5.1%
Activity: 5.1% Activity: 5.1% Activity: 5.1%
Thanks: Gave 984, Got 1,706
Posts: 12,506
scouse: Cyberheaters idea is excellent and is how rear projection TV's work.

Using electronic keystone correction or electronic zoom is a no no for good image quality. Both will substantially reduce resolution.

First rule of FRONT PROJECTION: PUT THE PROJECTOR IN THE CORRECT PLACE.

Of course the pj position is relative to the screen to moving the screen, if you can do it, is also a good solution. Moving the screen is the cheapest and best solution for image quality.

Gordon
  Quote
Old 30-05-2005, 9:42 PM   #8
Assured Advertiser
 
Joe Fernand's Avatar
Join Date: Jan 2002
Location: The Borders
Experience Points:
36,531, Level: 46
Points: 36,531, Level: 46 Points: 36,531, Level: 46 Points: 36,531, Level: 46
Activity: 20.9%
Activity: 20.9% Activity: 20.9% Activity: 20.9%
Thanks: Gave 205, Got 1,344
Posts: 14,186
scouse258

You could take the mirror idea a stage further and build a false wall incorporating a rear projection screen and then sit the projector behind the screen.

You can purchase custom rigs for the projector which incorporate adjustable mirrors and projector mount (costly) or build your own.

See http://www.draperinc.com/RearProject...ms/RPXLite.htm

Best regards

Joe
  Quote
Post Reply

Powered by  
 Latest popular product prices
Aiptek PocketCinema T15 
4 prices from
 £90.53 Click to show/hide the offers

Optoma Pico PK120 
3 prices from
 £134.99 Click to show/hide the offers

Acer C110 
2 prices from
 £149.95 Click to show/hide the offers

Dukane ImagePro 8758 
1 price
 £192.98 Click to show/hide the offers

Optoma Pico PK301 
4 prices from
 £248.97 Click to show/hide the offers

Optoma DS211 
6 prices from
 £228.96 Click to show/hide the offers

Acer X110P 
7 prices from
 £238.75 Click to show/hide the offers

Benq MS500 
5 prices from
 £238.00 Click to show/hide the offers

 Updated February 13th at 3:30am. Prices include delivery.


Thread information and display options
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off